Download Hart, Rachel. Folic Acid. KNH 413 – Medical Nutrition Therapy II

Hart, Rachel. Folic Acid. KNH 413 – Medical Nutrition Therapy II. Miami University,
Oxford, Ohio, Spring 2013.
Folic Acid (Folate or Vitamin B9)
1. What is the nutrient?
Folic acid is a B vitamin that helps the body make new, healthy cells, convert
food into energy, maintain proper brain finction, aids in RNA and DNA
synthesis, and works with vitamin B12 to help make red blood cells and help
iron work properly in the body (National Institutes of Health [NIH], 2013).
Folic acid also is extremely important in pregnancy and reduces major birth
defects in the fetus. It is a water-soluble vitamin that is not stored in the
body and is excreted through the urine. Folic acid is the synthetic form of the
vitamin found in fortified foods and dietary supplements, while folate is the
naturally occurring form of the vitamin (National Institutes of Health [NIH],
2013).
2. What is the RDA/DRI for the nutrient?
Recommended Dietary Allowances (RDA) for Folic Acid
Age
Birth to 6 months*
7–12 months*
1–3 years
Male
65 mcg DFE*
80 mcg DFE*
150 mcg DFE
Female
Pregnant
Lactating
65 mcg DFE*
80 mcg DFE*
150 mcg DFE
4–8 years
200 mcg DFE 200 mcg DFE
9–13 years
300 mcg DFE 300 mcg DFE
14–18 years
400 mcg DFE 400 mcg DFE
19+ years
400 mcg DFE 400 mcg DFE
* Adequate Intake (AI)
(National Institutes of Health [NIH], 2013)
600 mcg DFE
600 mcg DFE
500 mcg DFE
500 mcg DFE
3. How is the nutrient metabolized?
Folic acid is itself not biologically active, but its biological importance is due
to tetrahydrofolate and other derivatives after its conversion to dihydrofolic
acid in the liver. Folic acid coenzymes play a vital role in DNA metabolism
through the synthesis of DNA from its precursors (thymidine and purines),
and the synthesis of the amino acid methionine, which is required for the
synthesis of a methyl group donor used in many biological reactions. The
addition of a methyl (-CH3) group (methylation) to a number of sites within
DNA may be important in cancer prevention. Folic acid coenzymes are
required for the metabolism of several important amino acids, such as the
synthesis of methionine from homocysteine. Folic acid deficiency can
therefore result in decreased synthesis of methionine and a buildup of
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homocysteine; a risk factor for heart disease as well as several other chronic
diseases (National Institutes of Health [NIH], 2013).
4. What are food sources of the nutrient?
 Leafy green vegetables
 Fruits
 Dried beans
 Peas
 Nuts
 Enriched breads
 Enriched cereals
 Other grain products
(National Institutes of Health [NIH], 2013)
5. What disease states alter the nutrients metabolism?
Although it is fairly common to have low levels of folic acid, alcoholism,
inflammatory bowel disease, and celiac disease can also cause folic acid
deficiency (University of Maryland Medical Center [UMMC], 2013).
6. What are the tests or procedures to assess the nutrient level in the
body?
Folic acid can be measured two ways by a folic acid test. The first test
measures the amount of folic acid in the liquid portion of the blood called the
plasma. This reflects a person's recent intake of folic acid in the diet. The
second measures the amount of folic acid in the red blood cells. This test
may be a better way than the plasma test because the amount of folic acid in
red blood cells measures the level when the cell was made, as much as 2
months earlier. This level is not usually affected by the amount of folic acid
in a person’s diet each day and is the more accurate way to measure the
body's level of folic acid (National Institutes of Health [NIH], 2013).
7. What are the drug-nutrient interactions?
 Antibiotics, Tetracycline -- Folic acid should not be taken at the
same time as the antibiotic tetracycline because it interferes with the
absorption and effectiveness of this medication. Folic acid either
alone or in combination with other B vitamins should be taken at
different times from tetracycline. All vitamin B complex supplements
act in this way and should be taken at different times from
tetracycline.
 Phenytoin (Dilantin) -- Phenytoin, an anti-seizure medication, may
lower levels of folate in the body. However, folic acid may interfere
with the way phenytoin works, raising the risk of seizures.
 Pyrimethamine (Daraprim) -- Folic acid may make pyrimethamine,
a drug used to prevent and treat malaria and to treat toxoplasmosis,
less effective.
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Chemotherapy medications -- Folic acid may raise the amounts of 5fluorouracil and capecitabine (Xeloda) to dangerous levels in the
body.
 Methotrexate -- Methotrexate, a medication used to treat cancer,
rheumatoid arthritis (RA), and psoriasis, reduces the amount of folic
acid in the body.
 Drugs That Lower Levels of Folic Acid -- These drugs may interfere
with the body's absorption of folate, and may mean that patients need
to take a folic acid supplement.
o Antacids
o H2 blockers
o Proton pump inhibitors
o Bile acid sequestrants
o Anti-seizure medications
o Nonsteroidal anti-inflammatory drugs (NSAIDs)
o Sulfasalazine (Azulfidine)
o Triamterene (Dyrenium)
o Cycloserine
o Pyrimethamine (Daraprim)
o Trimethoprim
(University of Maryland Medical Center [UMMC], 2013)

8. How is the nutrient measured?
Folic acid is measured in micrograms per day (mcg/day) (National Institutes
of Health [NIH], 2013).
9. What is the UTL?
Tolerable Upper Intake Levels (UL) for Folic Acid
Age
Birth to 6
months
7–12 months
1–3 years
Male
Not possible to
establish*
Not possible to
establish*
300 mcg
Female
Pregnancy
Lactation
Not possible to
establish*
Not possible to
establish*
300 mcg
4– 8 years
400 mcg
400 mcg
9–13 years
600 mcg
600 mcg
14–18 years
800 mcg
800 mcg
800 mcg
800 mcg
19+ years
1,000 mcg
1,000 mcg
1,000 mcg 1,000 mcg
*Breast milk, formula, and food should be the only sources of folic acid for
infants
(National Institutes of Health [NIH], 2013)
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10. What are the physical signs of deficiency?
Folic acid deficiency can cause anemia, poor growth, tongue inflammation,
gingivitis, loss of appetite, shortness of breath, diarrhea, irritability,
forgetfulness, and mental sluggishness (University of Maryland Medical
Center [UMMC], 2013). If pregnant women do not get enough folic acid, their
children may suffer from neural tube birth defects, including cleft palate,
spina bifida, and brain damage (University of Maryland Medical Center
[UMMC], 2013).
11. What are the physical signs of toxicity?
At the recommended daily allowance, side effects from folic acid are rare.
Very high doses can cause stomach problems, sleep problems, skin reactions,
and seizures. People should talk to their doctor before taking more than 800
micrograms of folic acid. Folic acid can hide the symptoms of an underlying
vitamin B12 deficiency, which can cause permanent damage to the nervous
system. Taking any one of the B vitamins for a long period of time can result
in an imbalance of other important B vitamins. For this reason, it is
suggested to take a B complex vitamin, which includes all the B vitamins
(University of Maryland Medical Center [UMMC], 2013).
References
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Folic acid. (2013). National Institutes of Health [NIH]. Retrieved from http://ods.
od.nih.gov/factsheets/Folate-HealthProfessional/
Vitamin B9 (Folic acid). (2013). University of Maryland Medical Center [UMMC].
Retrieved from http://www.umm.edu/altmed/articles/vitamin-b9000338.htm
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